Explain the rational choice theory with these hypothetical crimes?

The woman should get the death penalty,if she realizes that she was extremely depressed she should have gotten help, she didn't and drowned her kids, that's her fault, sadly I actually heard about a case just like this a while a go, and her case held up in court, it shoudn't have, but it did . As for the man, he should also get death, I would hope that it would not hold up and I don't think it would either.